Chapter 33 Notes Invertebrates
Concept 33.1 Phylum porifera: - asymmetric - ex. sponges - sessile adults, larva may swim - have no nerves or muscles; individual cells can sense and react to environmental changes
Concept 33.1 - filter-feeders; choanocytes, or collar cells, ingest food filtered through the sponge - most are hermaphrodites
Concept 33.1
Concept 33.1
Concept 33.2 Phylum Cnidaria: - radial symmetry - ex. jellyfish, hydra, sea anemones, coral - have stinging cells called nematocysts or cnidocysts; eject a barbed thread - contain a gastrovascular cavity; single opening
Concept 33.2
Concept 33.2 - sessile forms are called polyp; free-floating are called medusa - diploblastic (epidermis and gastrodermis); between layers is the mesogloea
Concept 33.2
Concept 33.2
Concept 33.2
Concept 33.2 There are 3 classes of Cnidarians: Hydrozoa: - ex. hydra, Portuguese man-of-war - most marine - both polyp and medusa stages; polyp is often colonial
Concept 33.2 Scyphozoa: - ex. jellies - all marine - polyp stage is reduced - free-swimming
Concept 33.2
Concept 33.2 Anthozoa: - ex. sea anemones, coral - all marine - medusa stage absent - sessile
Concept 33.2
Concept 33.2 Phylum Ctenophora: - means “comb-bearer” for the eight rows of fused cilia - ex. comb jellies - tentacles contain colloblasts to capture prey
Concept 33.3 Phylum Platyhelminthes: - ex. Flatworms, flukes, tapeworms - bilateral symmetry - unsegmented - triploblastic; acoelomates (no body cavity)
Concept 33.3 Class Turbellaria: - flatworms - free-living - rely on diffusion for movement of food, oxygen, and waste - asexual and sexual reproduction; can regenerate lost parts
Concept 33.3
Concept 33.3
Concept 33.3 Class Trematoda: - ex. blood flukes, liver flukes - all parasitic: feed on veins/organs of host - hermaphroditic
Concept 33.3 Class Cestoidea: - ex. tapeworms - all are parasites - attach to intestinal wall with scolex and absorb food from host
Concept 33.3
Concept 33.3 Phylum Rotifera: - psuedocoelomates - freshwater - complete digestive tract - fluid in psuedocoelom acts as a hydrostatic skeleton
Concept 33.3
Concept 33.3 Phylum Nematoda: - ex. roundworms - complete digestive system and closed circulatory system: blood is contained in vessels - decomposers and parasites
Concept 33.4 Phylum Mollusca: - ex. snails, slugs, clams, squids, octopuses - body consists of three parts: foot, visceral mass, mantle - open circulatory system - gas exchange is via gills, lungs, or the body surface (diffusion)
Concept 33.4
Concept 33.4 Class Polyplacophora: - ex. chitons - use foot to cling to rocks - simple nervous system and sense organs
Concept 33.4
Concept 33.4 Class Gastropoda: - “stomach-foot” - ex. snails and slugs - torsion: uneven growth in the visceral mass; rotates 180 degrees - exchange gases via gills; use mantle cavity
Concept 33.4
Concept 33.4 Class Bivalvia: - “hatchet-foot” - ex. clams, oysters, mussels - foot used for motility or anchorage - suspension feeders - no distinct head
Concept 33.4
Concept 33.4 Class Cephalopoda: - “head-foot” - ex. squid and octopus - carnivores; beak-like jaw to crush prey - have chromatophores to allow them to change colors - shell is reduced or absent
Concept 33.4
Concept 33.5 Phylum Annelida: - ex. earthworms, leeches - all are segmented - setae project from cuticle - closed circulatory system; aortic arches
Concept 33.5 - developed nervous system with two ventral, solid nerve cords and cerebral ganglia - complete digestive system: mouth-crop-gizzard-intestine-anus - sexual and asexual reproduction - tactile organs, chemoreceptors, balance receptors, and photoreceptors
Concept 33.5
Concept 33.5
Concept 33.5 Class Oligochaeta: - ex. earthworm - all have setae - help aerate soil and cycle nutrients
Concept 33.5 Class Hirudinea: - ex. leeches - mostly freshwater - either carnivorous or parasitic
Protosomia Class Polychaeta: - primarily marine - parapodia with bristles; can be used for locomotion and gas exchange - largest class
Protosomia